Door structure for refrigerators



Oct. 15, 1957 H. L. souTHwoRTH 2,809,402

DooR STRUCTURE FOR RRFRIGERAToRs Filed Jan. 5. 195s iml 5 54 I H6 7 AHORA/frs 2,809,402 DOOR STRUCTURE FOR REFRIGERATORS Herbert L. Southworth, San Francisco, Calif., assigner to S. G. Anderson, San Francisco, Calif.

Application January 5, 1953, Serial No. 329,647

` s claims. (Cl. :v -3s) This invention relates to doors and more particularly to a door and frame structure suitable for cold storage refrigerators of the type in which the temperature may reach as low as F.

In refrigerator door installations, difficulty is frequently experienced in preventing warpage of the door. Such warpage is caused to a great extent by the flow of vapor to and from the interior of the door and results in undesirable Iheat leakages in many instances.

It has been customary in the past to guard against warpage by the addition of structural members in the manufacturing process. This results in the weight of the door Ibeing increased thus making the opening and closing of the same a more strenuous operation and increasing the likelihood of injury to the door and frame when the door is slammed shut.

In addition, when the temperature inside the refrigerator is very'low,k the door and frame tend to stick together due to freezing of any moisture or water vapor on the door or door frame. This creates a resistance to opening a closed door which, when added to the effort required to move the door, sometimes necessitates the use Of'extraor-dinary mechanical means to pry the door open.

The main object of the present invention is to provide a novel door and frame construction which not only eliminates warpage of the door, but :also results in the door being made considerably lighter than heretofore possible.

Another object of the invention is the provision of a door and frame construction in which freezing of the door to the frame is effectively prevented.

Still another object of the invention is the provision of a novel latch mechanism for locking the door shut and which mechanism is actuatable from inside the refrigerator so that there is no possibility of a person being locked within the` refrigerated space.

Yet another object of the invention is the provision of a novel means for hingedly securing the door to the frame so Las to permit exact registration of the door and corresponding frame opening during manufacture and also when the door is installed in the frame.

Another object of the invention is the provision of a novel latch actuating means including a pair of handles opera-ble from opposite sides of the door and constructed to prevent undesirable transmission of heat from one handle to the other.

Other objects and advantages will be apparent from the following specification and from the drawings.

Fig` l is a front elevational view of a door and surrounding frame showing my new construction. A portion of the door is broken away to show the frame strueture.

Fig. 2 is an enlarged horizontal cross-sectional view through the door as, taken along lines 2 2 of Fig. 1 and illustrating the general construction of the same and showing the hinge structure.

"nited States Patent C) Fig. 3 is a greatly enlarged horizontal cross-sectional view through Ithe door jamb on the latch side of the door tand showing the door slightly open relative to said jamb.

Fig. 4 is a greatly enlarged fragmentary cross-sectional view through the sill of the door lframe as taken along lines 4--4 of Fig. l and showing the door partly open relative to said sill and illustrating the manner of installing the sill in a concrete iloor.

Fig. 5 is an enlarged horizontal cross sectional view through the latch mechanism as taken along lines 5-5 of Fig. l.

Fig. 6 is a greatly enlarged vertical cross-sectional view through the latch bolt as taken along lines 6-6 of Fig. 5.

Fig. 7 is a longitudinal sectional view through a portion of the latch bolt as taken along lines 7-7 of Fig. 6.

Fig. 8 is :a vertical cross-sectional view through the jamb and door adjacent the hinge structure showing the latter in section.

In detail, the invention comprises a refrigerator door lgenerally designated 1 and a door frame 2. The frame comprises la pair of vertical, opposed jambs 3, 4, a head piece 5 and a sill 6.

The frame 2 includes a door stop 7 (Fig. 3) extending along the length of the jambs 3, 4 and the head piece 5. This .door stop is preferably about 21/2" x 21/2l in crosssection for a 3 x 66 standard door and will, of course, vary with the size of the door desired.

The jambs 3, 4 are preferably constructed from two lengths 8, 9 of SAS plywood secured together and to the door stop as best seen in Fig. 3 with the outer length 9 overlapping the stop 7 and the inner length 8 abutting said stop.

The door 1 is formed with an inner hollow body defined by plywood walls as best seen in Figs. 2, 3. The inner door body is preferably formed with an outer strip 12 of 5%" plywood which peripherally encircles the door and a pair of opposed relatively thin plywood sheets 13, 14 butted against the inner margins of strip 12.

To provide additional reinforcement around the margins of the doors an inner strip 15 of SAB" plywood, slightly narrower than strip 12 is secured to the latter and also to the sheets 13, 14 as seen .in Figs. 2, 3, 4 thus providing a strong ycorner joint. At spaced points along the width and length of door 1 are stiffeners 18, preferably of Fys plywood, which extend between and are secured to the outer sheets 13, 14.

By the above `described structure, it will be apparent that an inexpensive, rigid hollow body is formed which may be filled with any desired insulation 19 such as the type known to the trade as Fiberglas inasmuch as the door is constructed of wood, the samel would be subject to warpage after a period of use due to the passage of vapor into and out of the interior of the door by the passage of vapor through the non-tight seams of the plywood layers.

To obviate such leakage, I provide a sheath of vapor' tight material around the door.

This sheath preferably comprises a channel member 21 of tough plastic having a bottom 22 and a pair of opposed legs 23, 24 (Fig. 3). This channel 21 is adherently `secured to the top, bottom and opposite lateral side edges of the door 1 -by any suitable cement with the bottom 22 engaging the outer plywood strip 12 and with the legs 23, 24 engaging the outer marginal surfaces of the plywood sheets 13, 14. In this connection, it is preferable that the plywood sheets 13, 14 be relieved as best seen in Fig. 3 to receive legs 23, 24 of channel 21 so that the outer surfaces of said legs are `coplanar with the outer surfaces of said sheets.

To complete the vapor tight sheath surrounding the inner door body I provide sheets 25, 26, of plastic similar to channel 21 and which sheets cover the outwardly directed faces of plywood sheets 13, 14 respectively. These sheets 25, 26 are preferably large enough to lap over a portion of legs 23, 24 of channel 21 so that a vapor tight joint may be effected by means of a suitable cement.

The material of channel 21 and sheets 25, 26 is preferably a fiberglass reinforced polyester resin of about 1/16 thickness. This material is extremely tough due to the fiberglass reinforcement and has the important characteristic of being substantially unaffected by extremes of temperature and other changes in atmospheric conditions. Such material is known to the trade by various trade-names such as Plexolite The plastic sheets 25, 26 may be conveniently installed with an integral backing of plywood similar to sheets 13, 14 if desired. In any event, such backing or sheets 25, 26 need not exceed about 1A in thickness for a 3 x 6-6 door such as described herein.

The legs 23, 24 of channel 21 may be notched at the points where the same is bent to form the corners of the door and the side edges of such notches butted together as indicated at 27 (Fig. 1) and cemented in any suitable manner to effect a vapor tight joint.

To prevent freezing of the door to the frame, I provide a ribbon 30 (Fig. l) of conductive rubber secured to the door engaging face 31 of door stop 7. This ribbon 30 is resilient and bendable in like manner as a strip of rubber, but is impregnated with fibers of material adapted to conduct electricity so that said ribbon, in effect, becomes a heating element. Thus, in addition to acting as a gasket, ribbon 30 also functions to heat the door and frame at their points of engagement. Preferably, the ribbon 30 is made in one length although several standard lengths may be joined together if desired. Electricity is conducted to said ribbon 30 by a cable 32 including a pair of wires 33, 34 which may be respectively connected to opposite ends of the ribbon 30 (Fig. l). The jamb members 8, 9 may be apertured as desired for passing said wires 33, 34.

The ribbon 30 of conductive material per se is old and no claim is made to the same herein except in combination with the door and frame. In the trade, the material forming the ribbon is sometimes referred to by the trade-name Uskon The sill 6 of the door frame preferably comprises an elongated relatively heavy block of redwood 39 extending between the jambs 3, 4 and, if the adjoining floor is of concrete, as is usually the case, the block 39 may be embedded in said concrete as best seen in Fig. 4. In such a case, the depth of the block 39 is preferably such that a metal plate 40 may be secured to the top of block 39 so that the upper surface of plate 49 is llush with the surface of the oor.

Preferably, the floor level within the refrigerator is slightly higher than the lloor level outside the refrigerator so that plate it? must be bent to provide a downwardly and outwardly sloping portion 4l against which the refrigerator door is adapted to seal. Inasrnuch as trucks and other vehicles are usually moved into and out of the refrigerator, during the normal use of the latter, the plate 4) is preferably made replaceable so that a new plate may be installed after the old one is worn.

To this end the redwood block 39 is provided along its longitudinal side edges with angles 42, 43 which may be secured to block 39 by wood screws 44. Angles 42, 43 are disposed with one leg horizontal as best seen in Fig. 4 and said legs may be tapped to receive screws 45 which are passed through countersunk holes in plate 40.

The sill block 39 is provided with an upwardly opening groove adjacent slanting portion 41 of plate 40 and which groove is adapted to receive therein the lower horizontal run 47 of ribbon 30 (Fig. 4). Additional grooves as required in block 39 may be provided to per- W"satsoaaoa mit ribbon 30 to be run laterally as at 48 from the plane of door stop 7 to the horizontal run 47.

From the above described structure, it will be apparent that the heating element or ribbon 30 will serve to heat the metal plate 40 which, being heat transmissible will, in turn, serve to locally heat the surface of engagement between plate 40 and the gasket on door 1.

The door gasket 50 may be in any convenient form but preferably is of a width about equal to the width of the heating element ribbon 30. This gasket 50 may be adherently secured to the inner leg 24 of channel 21 along the vertically extending margins of the door and along the head piece.

At the lower edge of the door, the gasket is directed along the outer side of the bottom 22 of channel 21 and extends in a horizontal run 51 along said bottom. It will be understood in this connection that the bottom edge of the door is biased as best seen in Fig. 4 so that the same is complementary to slanted portion 41 of sill plate 40.

It will thus be apparent that the gasket 50 is heated along its entire length by the heating element 30 which, when conducting electricity, effectively prevents freezing of the door to the frame.

Inasmuch as the locking mechanism for the door must be arranged so that no vapor can pass therethrough into the interior of the door, I have provided a novel locking mechanism for this purpose having certain additional advantages which will subsequently be pointed out.

Referring to Figs. l, 5 and 7 the locking mechanism, generally designated 55, comprises a latch bolt housing 56 which may conveniently be formed from a length of pipe. One end of housing S6 is passed through a suitable aperture formed in plywood strips 12, 15 and is secured at its opposite end by means of an integral flange 57 to a vertical plywood stifening strip 54 similar to the stiffeners 18 hereinbefore described.

Reciprocably mounted in housing 56 is an elongated latch bolt 58 which is provided at its outer end with a biased portion 59 adapted to engage a conventional strike plate (not shown) on the frame in the usual manner. The latch bolt 58 is urged to projected position at all times by a compression spring 60 extending between the inner end of housing 56 and the inner end of latch bolt 58 (Fig. 5). The latch bolt 56 is preferably provided with a reduced inwardly extending portion 61 to serve as a retainer for spring 60.

Intermediate its ends, latch bolt 58 is provided with an upwardly opening recess 62 which is adapted to receive therein the lower ends of a pair of transversely spaced cams 63, 64 (Figs. 6, 7). Cams 63, 64 are provided at their upper ends with cylindrical portions 52, 53 respectively which are rotatably supported in upwardly extending ears 65, 66 integral with housing 56. As best seen in Fig. 7, the lower ends 67, 68 respectively of cams 63, 64 are adapted to engage the inner end 69 (Fig. 7) of recess 62 when said cams are rotated counterclockwise (Fig. 7) and urge said latch bolt inwardly for retractng the latch bolt to permit opening the door.

Cylindrical portion 52 of cam 63 is centrally provided with a horizontally extending square hole for receiving the complementary formed square end 70 of handle 71 (Figs. 6, 7). Handle 71 is passed through a suitable opening in the outer face of door 1 and is rotatably supported in a bearing plate 72 secured by any suitable means such as wood screws to the plywood sheet 13. In an identical manner, handle 73 is carried by the inner plywood sheet 14 on the inner face of the door (Fig. 5) for operating cam 64. Spring retainer rings 74, 75 may be received in complementarily formed annular grooves in cylindrical portions 52, 53 for preventing shifting of cams 63, 64 axially of handles 71, 73.

From the above described structure, it will be apparent that downward swinging of either handle will urge the latch bolt 58 to retracted position. Upon slamming the door,

the latch bolt will be retracted inthe usual manner `against the urging of spring 60.

The ears 65, 66 which rotatably support Ythe cams 63, 64 are provided with a hood .portion 77 which may be integrally welded to said ears .and ,also .to the upper side of pipe housing 56 so as to seal the inside of the door against vapor which might .pass through the housing 56 alongside latch bolt 58.

T o limit the outward movement .of latch bolt 58 to its projected position, the upper side of the pipe housing 56 may be extended inwardly as at 76 (Fig. 7) to prevent clockwise rotation of cam 63 beyond .the full line position of Fig. 7.

Completely surrounding the latch mechanism hereinbefore described is a casing generally designated 78 having top and bottom walls 79, V80, lateral sidewalls 81, 82 and inner and outer end walls 83, `84. This casing 78 is completely vapor tight being formed from sheets of fiberglass reinforced plastic with the walls adherently secured together by cement. may be provided integral with said casing to assist in cementing the casing to the inner sides of plywood sheets 13, 14. Said casing may be suitably apertured for passing handles 71, 73 and latch bolt housing 56, but inasmuch as the casing is adherently secured to the plywood door sides no escape of vapor between the casing and the plywood is possible. In addition, it will be understood that should vapor enter the interior of casing 78, either through the latch bolt or handle openings, entrance of such vapor to the hollow interior of the door is nevertheless effectively prevented by the vapor tight casing 78.

lt should be noted at this point that one door handle may be operated independently of the other and if a locking means (not shown) is provided on the outside of the door to prevent unauthorized entrance to the refrigerated space, the inner handle may nevertheless be operated to open the door if someone is inadvertently locked inside. This satisfies the safety requirements of existing state statutes.

The latch mechanism hereinbefore described has the additional advantage of not providing a metallic connection between the inner handle 73 and outer handle 71. Thus the space 87 between cams 65, 66 eliminates heat loss through the conduction of heat from handle 71 to handle 73 and prevents the former from becoming uncomfortably cold.

The present invention also contemplates the provision of a novel hinge structure by which the door is more readily fitted to the frame than heretofore possible and by which hinge structure entrance of vapor to the interior of the door is effectively prevented.

Referring to Figs. 2 and 8, the inner plywood strip 8 of jamb 3 is cut away to receive the frame leaf 90 and Valso the door leaf 91 (Fig. 8). Leaves 90, 91 are pivotally secured together in the usual manner as by hinge pin 92 (Fig. 2).

Door leaf 91 is not secured to the door in the usual manner, but a hooked plate 93 somewhat similar to a hinge leaf is secured to the outer strip 12 of the door by screws 94. Along the upper edge of plate 93 the same is formed with an outwardly projecting extension 95 which terminates in a downturned hook portion 96. As best seen in Fig. 8 the extension 95 extends over the upper edge of door leaf 91 and, as seen in Fig. 2, the upper portion of frame leaf 90 is provided with an upwardly opening notch 97 for receiving the hook portion 96.

By this structure, when the door is installed, the door leaf 90 may first be secured to the frame as by screws 98 in the usual manner and then the door leaf 91 may be swung outwardly from the frame and away from door leaf 90. When the door leaf 91 is thus in its open position the door may be hooked onto said door leaf by hook 96. Only one hinge structure has been described, but it will be understood that all hinges, generally designated 99 (Fig. l) are the same.

Outwardly extending flanges 85, 86

By the .use of this hinge structure, there are `no holes required .to be made in the door at the `time the same is installed at lthe site, consequently there is no possibility of the vapor .tight seal being punctured by the workmen installing :the door. It, therefore, follows that when the door lis constructed .at the factory, the `necessary precautions and tests may follow to insure vapor tightness with the assurance that such tightness will -not be subsequently impaired.

By the present invention, the weight of the refrigerator door may be reduced three -or four times over conventional without reducing the insulating qualities of the same and at the same time .insuring against warpage of the door with its attendant heat loss.

The detailed description herein given of the invention is not to be taken as restrictive of the same as it is obvious that various minor changes in design ymay be made without departing from the invention as defined in the following claims.

I claim:

l. A refrigerator door comprising a hollow inner body having a pair of opposed faces, top and bottom edges and opposite lateral side edges, a vapor tight sheath of relatively tough sheet material secured to said body and enclosing the same for preventing movement of vapor to and from the space within said inner body for preventing warpage of said door, said sheath comprising channel members secured along said top and bottom edges and said side edges with the legs of said channel members extending inwardly of said faces and in engagement with the latter and sheets of said material covering said faces respectively and in lapping relation along their margins with the adjacent legs of said channels, said sheets and the legs of said channels being adherently secured together to form vapor tight joints.

2. A refrigerator door comprising a hollow inner body having a pair of opposed faces, top and bottom edges and opposite lateral side edges, a vapor tight sheath of relatively tough sheet material secured to said body and enclosing the same for preventing movement of vapor to and from the space within said inner body for preventing warpage of said door, said body being internally provided with a latch mechanism including a latch bolt extending outwardly of one of said lateral side edges, a casing of vapor tight material surrounding said mechanism for preventing movement of vapor to and from said space through said latch mechanism.

3. A refrigerator door comprising a hollow inner body having a pair of opposed faces, top and bottom edges and opposite lateral side edges, a vapor tight sheath of relatively tough sheet material secured to said body and enclosing the same for preventing movement of vapor to and from the space within said inner body for preventing warpage of said door, said body being internally provided with a latch mechanism including a latch bolt extending outwardly of one of said lateral side edges, a casing of vapor tight material surrounding said mechanism for preventing movement of Vapor to and from said space through said latch mechanism, the other of said lateral side edges being provided with laterally outwardly projecting members formed at their outer ends with downwardly turned flanges, said members being secured to said other side edges in vapor tight relationship whereby said door is adapted to be supported by said members on the corresponding leaves of a pair of hinges without the use of removable fasteners.

4. A refrigerator door comprising a hollow inner body having a pair of opposed faces, top and bottom edges and opposite lateral side edges, a vapor tight sheath of relatively tough sheet material secured to said body and enclosing the same for preventing movement of vapor to and from the space within said inner body for preventing warpage of said door, a latch mechanism within said space including a latch bolt extending outwardly of one of said lateral side edges, a housing for reciprocably receiving said bolt and a pair of handles extending outlwardly of the opposite faces of said door respectively for actuating said bolt, separate means carried by said handles respectively for actuating said bolt by either one of said handles independently of the other, said last mentioned means being spaced apart to prevent conduction of heat from one handle to the other.

5. A refrigerator door comprising a hollow inner body having a pair of opposed faces, top and bottom edges and opposite lateral side edges, a vapor tight sheath of relatively tough sheet material secured to said body and enclosing the same for preventing movement of vapor to and from the space within said inner body for preventing warpage of said door, a latch mechanism within said space including a latch bolt normally projecting outwardly of one of said lateral side edges, a housing for reciprocably receiving said bolt and a pair of handles extending outwardly of the opposite faces of said door respectively for actuating said bolt, bearing members icarried by said housing and rotatably supporting said handles at their inner ends adjacent said bolt, bolt engaging members carried by said inner ends and spaced from each other for independently retracting said bolt depending upon which handle is operated.

References Cited in the file of this patent UNITED STATES PATENTS 

